1. Field of the Invention
The present invention relates to a method and an electronic device of file system prefetching and a boot-up method. More particularly, the present invention relates to a method of file system prefetching during booting multiple operating systems (OS), an electronic device executing the method, and a corresponding boot-up method.
2. Description of the Related Art
A mobile device today, such as a smart phone, tablet computer, personal digital assistant (PDA), game console and the like, may include multiple processors. The multiple processors may execute multiple operating systems. For example, the main processor may execute the main operating system that provides applications and graphical user interfaces to serve the user, while an auxiliary processor may execute an embedded operating system to control a peripheral device, such as a wireless communication module of the mobile device.
In a typical multi-processor mobile device, the processors may operate according to different clock frequencies and the operating systems may have different levels of complexity. As a result, the time each processor takes to boot up the corresponding operating system is different. When the power of a multi-processor mobile device is powered on, each processor begins to boot up its operating system. The processors have to perform a booting state synchronization for establishing the communication mechanism among the processors and synchronizing the booting states of the operating systems to ensure a correct booting of the multi-processor multi-system mobile device.
After the booting state synchronization, the main operating system running on the main processor copies the data required for booting the main operating system from a slower non-volatile storage, such as a flash memory, to a faster volatile storage, such as a dynamic random-access memory (DRAM). The main operating system accesses the aforementioned data stored in the volatile storage during its booting sequence.
The bottleneck of booting the main operating system usually occurs on the aforementioned data copy from the non-volatile storage to the volatile storage. For example, the data copy may take 40% of the total booting time of the mobile device.